Electrical static eliminator devices such as ionizing bars, ionizing blowers, and single point static eliminators function to eliminate static electricity by emitting ions into the area proximate a surface or device carrying undesirable static charges. Ionizing bars, for example, are typically employed in printing machinery and used to prevent particles from contaminating the paper during the printing process and to prevent handling or processing problems. Ionizing blowers, on the other hand, are typically used at electrostatic discharge (ESD) safe work stations to prevent electrostatic discharge damage to sensitive electrical components.
The prior art methods of checking the performance of such static eliminator devices are severely limited. In one example, an indicator lamp is provided and powered by the same power supply which provides power to the static eliminator device. If power is supplied to the static eliminator device, the lamp is illuminated. Thus, this lamp only indicates whether power is being supplied from the secondary transformer of the power supply. Therefore, it provides no indication of whether each emitter point of the static eliminator device is actually ionizing and thus provides a false positive indication when an individual emitter point is fouled with particulate matter, disconnected from the transformer, and/or grounded. In a given manufacturing facility, it is not uncommon for one or more emitter points to become fouled over time or shorted thus severely reducing the performance of the static eliminator device.
In another prior art device, a capacitive plate is permanently incorporated on the end of the body of an ionizing bar and a lamp is connected to the capacitive plate. This device lets the user know whether or not voltage is being applied all the way along the bar, but, again, provides a false positive reading if one or more individual emitter points are fouled or shorted and thus not ionizing.
Such prior art devices fail to sense both the ion flow from each point of the static eliminator device and the presence of a proper voltage at such an ionizing point to thus accurately detect both the fouled point condition and a shorted point condition.
Also available are other prior art devices which include a family of laboratory and hand-held devices that typically incorporate an electrostatic voltage metering device with a plate which can be charged. The ability of the static eliminating device to discharge the plate is monitored. The typical size of the plate utilized is too large to discern problems with individual ionizing points, and the typical testing method must allow for charging and decay times that do not permit prompt analysis of the performance level of individual ionizing points. Also, these prior art devices typically include rather complex circuitry, require a power source, and are thus expensive to manufacture. Examples of prior art indicators include U.S. Pat. Nos. 5,570,266 and 5,017,876 incorporated herein by this reference.